Cooper Energy Limited (Cooper Energy) is the titleholder of Petroleum Retention Leases VIC/RL13 (Basker Field) and VIC/RL 14 (Manta Field) in the Gippsland Basin and are located approximately 55 km southeast of the Orbost Gas Plant on the Victorian coast (Figure 1 1). These permits along with the Gummy field (which is not the subject of this Environment Plan) are known as BMG.
BMG infrastructure (7 wells) has been in a non-production phase (NPP) since 2010. Cooper Energy intends to abandon the existing BMG infrastructure in two phases:
•          Phase 1 – Plug and abandon the existing Basker and Manta wells with removal of minor infrastructure items (covered under this Environment Plan);
•          Phase 2 – Installation support vessel (ISV) decommissioning of remaining seabed infrastructure (activity will be the subject of separate Environment Plan).
Activities are anticipated to commence mid- 2018 and take approximately 80 days to complete all activities, excluding weather and operational delays. During this period, any of the activities described in the EP may be undertaken, with normal operations conducted 24-hours a day.
Phase 1 Abandonment Program to be completed by a Mobile Offshore Drilling Unit (MODU) (Ocean Monarch) within a 500 m exclusion zone and 2 km operational area.
Activities included in the scope of the EP include:
•          Pre-lay of MODU moorings;
•          Disconnection and laydown of infield flowlines and service lines from the wells;
•          Plug and abandonment of the BMG Wells; and
•          Drilling and removal of subsea trees and wellheads.
Activities excluded from the scope of this EP are:
•          Decommissioning / removal of infield flowlines and pipelines (Phase 2 abandonment);
•          Vessels / MODUs transiting to or from the operational area.  These vessels are deemed to be operating under the Commonwealth Navigation Act 2012 and not performing a petroleum activity.
The MODU will be towed to location where it will be moored prior to commencing activities.  Anchors may be placed on the seabed and tested by the support vessels prior to the MODU arriving.  Eight anchors will be required, with each having a footprint of approximately 30 m2. Each anchor is connected to large chain (83 mm) which runs along the seabed towards the MODU for approximately 1100 m before rising towards the MODU.  A 500-m exclusion zone will be in place around the MODU for the duration of the activities.
The MODU will be supported by two or three anchor handling, tow and support (AHTS) vessels.  One vessel will remain on standby and in attendance to the MODU throughout the workover program.